JPH029359Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an induction melting furnace with an improved shield structure using an inert gas.

[Technical background of the invention and its problems]

In recent years, induction melting furnaces have been widely used in metal melting work, but since melting is usually carried out in an open atmosphere, there is a problem of reactions with O ₂ gas in the atmosphere and H ₂ gas caused by moisture. be. For example, in the case of copper, it may react with H ₂ gas and cause hydrogen embrittlement because it contains it, and it may also react with O ₂ gas, resulting in a reduction in yield due to oxidation loss.

Therefore, it is not possible to perform high-purity melting when the melting chamber is open to the atmosphere. Conventionally, a nozzle is installed at the top of the melting chamber, and an inert atmosphere is injected from the nozzle toward the molten metal. A method of dissolving it inside is also adopted.

However, since the refractory material that makes up the melting chamber is porous, gas and moisture from the atmosphere enter through the melting chamber and react with the gas from inside the melting chamber, making it impossible to perform high-purity melting. It has not been possible to obtain high-purity pure copper with a good yield, which is sufficient for electrical component materials.

[Purpose of invention]

The purpose of the present invention is to provide an induction melting furnace that eliminates the above-mentioned drawbacks, blocks reactions with gases in the atmosphere, can obtain highly pure metal, and improves yield by preventing oxidation loss. That is.

[Summary of the idea]

The present invention has an airtight structure for the furnace frame that supports the outer periphery of the melting chamber made of refractory material, and an airtight structure for the furnace lid that is attached to the top of the melting chamber so that it can be opened and closed. , is characterized in that an inert gas supply mechanism is provided to maintain the melting chamber in an inert gas atmosphere from the inside and outside.

[Example of idea]

An embodiment of the present invention will be described in detail below with reference to the drawings.

In the figure, reference numeral 1 denotes a crucible-shaped melting chamber made of refractory material, and this melting chamber 1 is placed on a furnace bottom refractory material 2. A heating coil 3 is installed on the outer periphery of the melting chamber 1.
is wound, and furthermore, return path iron cores 4 are arranged at predetermined intervals around the outer periphery, and are fixed to a furnace frame 5 surrounding the melting chamber 1 with bolts 6. The feeding terminals 7, 7 connected to the upper and lower parts of the heating coil 3 are
It is connected to an external power source by passing through a feeding insulating plate 8 formed of a laminated glass plate or the like that closes the feeding outlet of the furnace frame 5 .

Further, the bolts 6 supporting the return magnetic path core 4 are
It is fixed through the furnace frame 5, and this protrusion is further covered by a furnace body sealing lid 9, so that the inside of the furnace frame 5 has an airtight structure.

Reference numeral 10 denotes a furnace lid made of a refractory material and covered with a metal plate on the outer periphery, and is attached to the upper part of the melting chamber 1 so as to be openable and closable. The furnace lid 10 is composed of a large lid 11 and a small lid 13 attached to a viewing window 12 in the center thereof so as to be openable and closable, and a gas seal gas seal 14 is inserted into these opening/closing parts. .

15 is a gas filling joint connected to an inert gas tank, and a gas filling pipe 16 connected to this is:
It branches into three directions, one of which is guided inside the furnace frame 5. The other gas-filled tube 16 is connected to the large lid 11.
The remaining gas filling tube 16 is connected to a ring-shaped gas outlet 18 formed in the lower part of the small lid 13 so as to surround the viewing window 12. ing.

In the figure, reference numeral 19 indicates a gas exhaust valve attached to the furnace frame 5, and reference numeral 20 indicates a molten metal.

Next, the operation of the induction melting furnace having the above structure will be explained.

First, the large lid 11 is opened and the material to be melted is put into the melting chamber 1. After that, the large lid 11 is closed, and the heating coil 3 is supplied from a power source (not shown) through the feeding terminals 7, 7.
A high-frequency or low-frequency current is applied to the material, and the material to be melted is heated and melted by this electromagnetic induction effect.

At this time, an inert gas such as nitrogen gas or argon gas is supplied from the joint 15 through the gas-filled pipe 16. The inert gas supplied to the furnace lid 10 is
Ring-shaped gas outlet 1 provided at the bottom of the large lid 11
7 and a ring-shaped gas outlet 18 provided at the bottom of the small lid 13 so as to surround the viewing window 12, the gas is injected into the melting chamber 1, and the upper surface of the molten metal 20 is shielded with an inert gas. On the other hand, the inert gas supplied inside the furnace frame 5 shields the melting chamber 1 formed of porous refractory material from the outside, prevents air and moisture from entering the melting chamber 1, and prevents the molten metal from entering the melting chamber 1. Gas reactions from the inside of 20 can be prevented.

Note that when adding small materials to adjust the composition of the molten metal 20 or inspecting the molten state, the small lid 13 is opened and closed, but the area of the viewing window 12 is small, and a ring-shaped gas ring is placed around it. Since the spout 18 is provided, it is possible to prevent atmospheric air from entering when the small lid 11 is opened.

As a result, the molten metal 20 is shielded by the inert gas on its upper surface, and the molten metal 20
Melting chamber 1 made of porous refractory material that holds
The surrounding area is also shielded with inert gas, so
High purity metal can be obtained by preventing reactions with H ₂ gas, etc., and oxidation loss due to reactions with O ₂ gas can also be prevented.

[Effect of idea]

As explained above, according to the present invention, since melting is carried out while keeping the inside and outside of the melting chamber in an inert gas atmosphere and shutting it off from the atmosphere, it is possible to manufacture high-purity metal and to improve the yield. A melting furnace can be obtained.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional front view of an induction melting furnace according to an embodiment of the present invention. 1... Melting chamber, 3... Heating coil, 5... Furnace frame, 7... Feeding terminal, 8... Feeding insulating plate, 9...
Furnace body seal lid, 10...Furnace lid, 11...Large lid, 1
2... Peephole, 13... Small lid, 16... Gas filled tube, 17, 18... Gas spout, 20... Molten metal.

Claims (1)

[Scope of utility model registration request] The metal furnace frame that supports the outer periphery of the melting chamber made of refractory material has an airtight structure, and the furnace lid is attached to the top of the melting chamber so that it can be opened and closed. It consists of a small lid attached to a perforated viewing window so that it can be opened and closed, and both of these lids have an airtight structure with a metal plate covering the outer surface of fireproof material, and a ring is attached to the periphery of the viewing window and the bottom of the large lid. An induction melting furnace characterized in that a gas injection port provided in a shape is attached, a gas filling tube is attached inside the furnace frame, and the gas filling tube and the gas injection port are connected to an inert gas tank.